使用ORACLE外部表装载复杂数据

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原文：http://www.oracle.com/technetwork/issue-archive/2013/13-jan/o13asktom-1886639.html

I am using SQL Loader to load data into tables from a flat file. Some sample data in the file might be:

我打算使用SQL Loader装载来自平面文件数据。样例数据如下：

12,smith,1234556@@1234567 @@876556612,1200
14,John,1234@@4567@@56789 @@12345@@45778@@34566@@23456,1345

The field values are empno, empname, phone numbers, and salary. The table structures are

表结构如下：

create table emp ( empno number(5) primary key, ename varchar2(10), Sal number(10,2) )
create table emp_contact ( empno references emp, phone_no number(10) )

I want to insert the data into the emp and emp_contact tables. I don’t know how many values for phone_no the file contains (the number of values for phone_no is not fixed). How do I insert the data into the tables?
我想将以上数据分别装入2个表中: emp和emp_contact
问题是：我无法确定第三列（电话号码）有多少个，此列不固定。我将如何将数据装载进表？

这个问题很狡猾，看上去我们必须将第三列拆成多行插入。
对于号称“21世纪神奇数据装载工具”

--SQL Loader 来讲也无法直接实现！！！
此处，我建议使用21世纪数据装载工具

--外部表解决。思路是：将平面文件装入外部表，然后通过编写SQL进行拆分，最后按特定插入规则一次性插入指定表中。
下面，看我演示：
--1）进行数据装载
create or replace directory my_dir as '/home/tkyte'
/

CREATE TABLE et
( "EMPNO" VARCHAR2(10),
"ENAME" VARCHAR2(20),
"TELNOS" VARCHAR2(1000),
"SAL" VARCHAR2(10) )
ORGANIZATION external
(
TYPE oracle_loader
DEFAULT DIRECTORY MY_DIR
ACCESS PARAMETERS
(
RECORDS DELIMITED BY NEWLINE CHARACTERSET US7ASCII
BADFILE 'MY_DIR':'t.bad'
LOGFILE 't.log_xt'
READSIZE 1048576
FIELDS TERMINATED BY "," OPTIONALLY ENCLOSED BY '"' LDRTRIM
MISSING FIELD VALUES ARE NULL
REJECT ROWS WITH ALL NULL FIELDS
(
"EMPNO" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"ENAME" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"TELNOS" CHAR(1000)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"',
"SAL" CHAR(255)
TERMINATED BY "," OPTIONALLY ENCLOSED BY '"'
)
)
location
(
't.dat'
)
)
/

SQL> select * from et;

EMPNO ENAME TELNOS SAL
————— ————— ————————————————————————————————————————————— ————
12 smith 1234556@@1234567@@876556612 1200
14 John 1234@@4567@@56789@@12345@@45778@@34566@@23456 1345

--2）编写拆分SQL
SQL> select empno, ename, sal, i,
substr( tnos,
instr( tnos, '@@', 1, i )+2,
instr( tnos, '@@', 1, i+1 )
-instr( tnos, '@@', 1, i) - 2 ) tno
from (
select to_number(et.empno) empno,
et.ename,
to_number(et.sal) sal,
column_value i,
'@@'||et.telnos||'@@' tnos
from et,
table( cast( multiset(
select level
from dual
connect by level <=
(length(et.telnos)
-length(replace(et.telnos,'@@','')))/2+1 )
as sys.odciNumberList ) )
)
/

EMPNO ENAME SAL I TNO
————— ————— ———— —— ———————
12 smith 1200 1 1234556
12 smith 1200 2 1234567
12 smith 1200 3 876556612
14 John 1345 1 1234
14 John 1345 2 4567
14 John 1345 3 56789
14 John 1345 4 12345
14 John 1345 5 45778
14 John 1345 6 34566
14 John 1345 7 23456

10 rows selected.

--注意：这里使用了cast multiset语法，column_value是TABLE(odciNumberList)中一列

--3）编写插入SQL
SQL> create table emp
2 ( empno number primary key,
3 ename varchar2(10),
4 sal number
5 );
Table created.

SQL> create table emp_contact
2 ( empno number references emp,
3 phone_no number
4 );
Table created.
\
SQL> insert all
when (i = 1) then into emp (empno,ename,sal) values (empno,ename,sal)
when (i > 0) then into emp_contact(empno,phone_no) values (empno,tno)
select empno, ename, sal, i,
substr( tnos,
instr( tnos, '@@', 1, i )+2,
instr( tnos, '@@', 1, i+1 )
-instr( tnos, '@@', 1, i) - 2 ) tno
from (
select to_number(et.empno) empno,
et.ename,
to_number(et.sal) sal,
column_value i,
'@@'||et.telnos||'@@' tnos
from et,
table( cast( multiset(
select level
from dual
connect by level <=
(length(et.telnos)
-length(replace(et.telnos,'@@','')))/2+1 )
as sys.odciNumberList ) )
)
/
12 rows created.

SQL> select * from emp;

EMPNO ENAME SAL
————— —————— —————
12 smith 1200
14 John 1345

SQL> select * from emp_contact;

EMPNO PHONE_NO
——————— —————————
12 1234556
12 1234567
12 876556612
14 1234
14 4567
14 56789
14 12345
14 45778
14 34566
14 23456

10 rows selected.

------------------------------------

Dylan Presents.

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